The present invention relates to improvements in bacon belly slicing machines and in particular, improvements in controlling the feed of bacon bellies into a rotating slicing blade. There exists today a variety of types of slicing machines which are utilized in bacon slicing operations. In this regard, the slicing machine may be of a continuous feed type, as for example, that disclosed in U.S. Pat. No. 3,880,035 granted Apr. 29, 1975. Another type slicing machine may be that which utilizes a retractable feeding mechanism which is retracted when a belly has been consumed and completely sliced, so that the next belly may be put in place, as disclosed in U.S. Pat. No. 2,642,910 granted June 23, 1953 or U.S. Pat. No. 3,144,893 granted Aug. 18, 1964.
In the case of either type machine, or any other type bacon slicing machine, as the trailing end of the belly approaches the blade, the pull of the knife influences the feed of the product. Usually, unless there is substantial weigh of bacon reacting against this or perhaps effective gripping of the tail by the feed means, the end piece will be pulled into the blade, leading to splattering and incorrect slice thickness and package weight. To compensate for this, a variety of feed means and hold down devices adjacent the blade have been utilized.
In the case of the feed means gripping the rear portion of the belly, an obvious disadvantage is that the portion gripped is not sliced but withdrawn. More importantly, in the case of continuous slicing operation, the feed is usually provided by an endless chain conveyor, with a plurality of bellies in an end to end relationship being fed into the blade. By such an arrangement, the trailing end of the belly is drawn uncontrollably into the blade. To compensate for this, pressure fingers and feet have been provided along with an overhead tractor mechanism as disclosed in U.S. Pat. No. 3,354,920. The upper conveyor in conjunction with a lower conveyor feeds the bellies to a predetermined point with the fingers and feet engaging the belly adjacent the blade, providing a drag opposite to that of the pull of the blade. However, once the belly leaves the upper conveyor drive, it is relatively loose and the hold down fingers and feet, while providing drag and some stabilization, are still apt to vibrate and do not provide the most accurate control of the feed of the product. In slicing, approximately 8-10" of belly slicing is not predictable, with random irregular slices and splattering resulting in incorrect or poor integrity of the sliced package portions and increased reject occurances.
An improvement on the foregoing is that disclosed in U.S. Pat. No. 3,880,035 aforementioned. There a spiked lower conveyor is utilized to a point short of the blade. Rather than an upper track, spring loaded shoes urge the bellies downward with a forward shoe and fingers provided to increase control over the feed adjacent the blade. A side finger is usually provided in both these arrangements to bias the belly laterally against a side rail to further aid in controlling the feed.
While these devices have been found satisfactory in many applications, it has become desirable to provide an improved feed means which is effective to a point closely adjacent to the blade and which will control, in an accurate manner, the feed of the belly beyond the conveyor or shoe arrangement.
In addition, since in either case slice thickness control, as for example, that disclosed in U.S. Pat. No. 3,910,141 and citations therein, is intended to regulate slice thickness by control of the speed of the conveyor drive, this control may be somewhat hampered by an arrangement which provides for indescriminate drag throughout slicing.